Identifying Toxic Mold

by Kimberley Jace on July 16, 2008

Toxic black mold growing on indoor surfaces, such as walls and ceilings, might be obvious. Toxic indoor mold has the same appearance as moldy bread. It’s a greenish-black “fuzzy-looking” stain that might consist of a number of individual mold spots; in heavy mold infestation, the mold spots will have converged into a black, fuzzy mass.

The ceiling of this room provided ample feeding ground for several types of mold.

But the color of indoor mold is also determined by what the mold is eating; mold that grows on old leather jackets in humid conditions is lighter green, while mold colonies behind certain types of vinyl wall covering might be pinkish or yellow.

Mold is a living thing, so it has certain life requirements. Mold can eat, and therefore grow on, any organic material — that is, anything living or that was once living. This includes all natural building materials. Mold can grow in or near plastic building materials if there is any organic component in the adhesive or adjacent surfaces to serve as the mold’s feeding ground. Mold can grow on a greasy film or a pile of dust.

Mold also needs the correct temperature to thrive; unfortunately, mold does best in the same indoor climate that most people prefer, with moderate temperatures.

Checklist: Where to Look for Mold

Although toxic indoor mold can eat any organic material, it always needs an ample source of water. Areas of high humidity, where moisture can condense, are perfect for mold. So you should begin your search for indoor mold wherever your home has a water source or is damp.

The Environmental Protection Agency suggests you check the places on the image above, as well as:

  • Bathroom floors, walls, and ceilings, especially near the faucets and drains of the sink and tub; floor and walls near the toilet; inside toilet tank and bowl. Check for bubbled wall or floor material, which might be a sign that toxic mold is hiding underneath.
  • Kitchen floors and walls, especially near the faucets and drain of the sink, the back wall of the below sink cabinet, and the area behind the refrigerator, especially if you have an automatic ice-maker.
  • Basement walls, ceiling, and floor. Check areas where joists in the basement ceiling exit the building and all entry and exit points for water pipes. Check areas near water heaters.
  • Crawl spaces, especially those with dirt floors.
  • Walls around air conditioning units.
  • Wall areas under and around windows.
  • Carpeting, anywhere it touches a wall.
  • Area around a washing machine.
  • Floors and walls near any aquarium, humidifier, or dehumidifier.
  • Attics, especially if the roof leaks anywhere. Check flashing around chimneys.
  • Closets, especially if ventilation is poor and leather items are stored there.
  • Upholstered furniture that has been exposed to excessive moisture.
  • Gutters along the outside of the house.
  • Overgrown foliage in garden or landscape areas.
  • Behind wallpaper, inside cabinets, and in other hidden areas.

When checking for mold, look for stains on walls and ceilings that might indicate moisture damage. Notice bubbled wall coverings, ceiling tiles, or vinyl flooring, cracked or peeling paint, and, of course, obvious areas of black, fuzzy mold.

Carefully inspect areas where you notice a mildew/mold odor, which often indicates the presence of moisture but does not necessarily mean toxic mold is growing there. Not all mold is toxic, and not all toxic mold has a musty odor. So odor alone is not a good indicator of whether your home has a problem.

And remember: the most dangerous toxic mold might be the mold you can’t see, because it’s hidden within walls, under flooring, under rugs, above ceilings, or behind furniture.

Hiring a Mold Inspector

If you’re thinking about hiring a professional to inspect your home for mold, you probably already suspect you have a problem. Unfortunately, the first signs of a mold problem are often recurring allergic reactions and illnesses among the home’s occupants that can’t be explained by other substances in the home. If your family is in this situation, it’s a good idea to have your home evaluated by a mold professional.

A professional inspector will evaluate your home for mold in a much more thorough manner than you can. The inspector will look within the home’s structure, under flooring and carpeting, above ceiling tiles, and even inside the walls. S/he might also take samples and test any mold s/he finds, which will tell you if the mold is a particularly deadly variety. But testing is expensive, and usually only confirms what visual inspection. Remember, all mold is a problem, because every variety can cause serious allergic reactions in sensitive people.

Advantages of Hiring a Mold Inspector

You have a flashlight and a pry bar, and nobody knows your home better than you. Can’t you just perform a thorough mold inspection yourself?

You can, and you probably have, inspected your home, but here are a few good reasons to hire a professional:

  • The inspector will know where to look. Mold inspectors will move furniture away from walls and check underneath carpeting if they think mold is present. The inspector will look at your upholstered furniture and bedding in a more objective way than you will, because we become accustomed to items in our own homes. The mold inspector will follow water pipes through the house, looking for areas where condensation might cause mold.
  • Inspecting a home poses its own risks. Mold inspection increases the inspector’s exposure to mold. Some inspectors, and all mold eradication professionals, wear full protective gear before they begin, to minimize this risk. When you do your own inspection, you’re the one being exposed.
  • Inspectors know how to check for mold without inadvertently disturbing it. Mold easily releases spores into the air, which can then land on another surface and start a new colony. Breathing in the spores triggers allergic reactions in sensitive individuals. Mold spores can drift on air currents, so mold you disturb in the basement might end up sending spores into a distant bedroom through the heating vents.

If you suspect your home might have a mold problem, but you can’t see where it’s coming from, it’s definitely a good idea to have a professional inspection. Hidden mold behind a wall can be affecting every member of the household, and the effects get worse over time.

If you suspect there might be a toxic mold problem in your school or place of business, insist on a professional inspection. Where the health of many people, especially children, is involved, it’s better to trust the pros.

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